The invention relates to an apparatus for pushing at least one hollow glass article from a dead plate of a glass forming machine along a curved path onto a conveyor belt.
In one known apparatus of this type, disclosed in US 5 527 372 A, a stream of air is directed eccentrically against the heel of a bottle, so that the greater part of the airflow passes around the bottle in the clockwise direction (FIG. 4) through the corner of the pocket of the pusher, while the lesser part of the airflow passes around the bottle in the anticlockwise direction. The discharge opening for the stream of compressed air is located at the bottom of the free end of each finger of the pusher. A thrust pad on the finger ends above the discharge opening. Nevertheless, the compressed air exiting from the discharge opening is deflected upwards between the thrust pad and the bottle. This has the result that the bottle in the known apparatus is not permanently in contact either with the thrust pad or with the face pad of the side wall. The positioning of the bottle on the conveyor belt is correspondingly uncertain. Furthermore, the consumption of air is comparatively large, since compressed air flows all around the bottle. The path of the compressed air to reach the free end of the finger is comparatively long and convoluted. This results in corresponding losses of pressure.
From published international application number WO97/26220 A1 are known a series of embodiments per se, which all have to do with the suction effect of a stream of compressed air exiting from a nozzle. In FIGS. 1 and 3 reference is made to circular nozzles, although in relation to the nozzle in FIG. 3 one could alternatively use a slot nozzle, similar to the slot nozzle in FIG. 14.
The principle is to be understood from FIGS. 14 to 17 of this publication. The compressed air is supplied to a main wall of the pusher through a passage and exits from a nozzle slot, as a rule at an angle to the main plane of the main wall. This angled exit has the result that the air stream makes contact with the face pad, as is shown particularly clearly in FIG. 15. The publication describes this as the so-called Coanda effect (see page 10, lines 24 to 29). In each case, approximately from the horizontal centre of the main wall of each pocket air is blasted in the direction of that corner of the pocket in which the bottle is to stand. This jetting of air into the bottle corners has the result that turbulence and build-up of air would arise there if one did not provide a suction aperture in the associated finger, as shown in FIG. 14.
It is the object of the invention to reduce the structural cost and the consumption of compressed air. However, the apparatus should also prevent the glass articles from being released unintentionally by the pusher at high angular velocities (high conveyor velocities or large track radii of the outer glass articles in multiple mold machines), before the pushed glass article has reached its final position on the conveyor belt. Such a premature release of the glass article from the desired position would lead to transportation errors.
This object is achieved by using a pusher which comprises a base portion and, for each glass article to be pushed, at least one thrust finger extending transversely from the base portion, wherein each thrust finger with the base portion defines a pocket to receive the glass article, the pusher including a nozzle for each pocket, and wherein from each nozzle compressed air can be blown such that a pressure below atmospheric pressure which draws the glass article into the pocket is created between the pusher and the glass article. Each nozzle is arranged in the region of a corner of the associated pocket such that the compressed air can be blown from the corner out between the base portion and the glass article. The apparatus is particularly suitable for the simultaneous pushing of two or more glass articles which have been manufactured in particular in a section of an I.S. (individual section) glass forming machine. The conveyor belt runs along all sections of the I.S. glass forming machine. Preferably, jets with a bore of about 2 mm diameter and compressed air at about 2.0 to 2.5 bar are used. It is recommended that the compressed air should be supplied in a timed manner, in other words only during those parts of the pushing cycle in which otherwise there would be the danger that the glass article would be freed in an undesired manner from its pocket of the pusher. The arrangement of the jet in the region of the corner of the associated pocket of the pusher has the advantage that the compressed air is blown outwards from this corner. Therefore, in the corner, this cannot lead to turbulence and a build-up of air. Sucking the compressed air from the corner is therefore superfluous. Additionally, for a positionally accurate delivery of the glass article onto the conveyor belt, the moment in time that the compressed air is switched off is no longer critical. The consumption of air is reduced, since the compressed air no longer has to flow around the glass article but only now flows through between the base portion and the glass article.
Because the nozzle is mounted on the base portion, there is a particularly short supply path for the compressed air up to the jet.
Because the nozzle can be mounted at different heights on the pusher, one may choose the optimum height level for the jet for any axial length of the glass article.
Because the compressed air is blown at an angle downwards from each nozzle one achieves an optimum utilisation of the compressed air for the achievement of the desired suction effect between the base portion and the glass article.
The fact that compressed air can be blown out from each nozzle at least approximately parallel to the base portion leads to a particularly low consumption of compressed air with good suction effect.
The compressed air can be blown from each nozzle in the direction of a cylindrical part of the glass article which has a maximum transverse dimension, thus, a gap of greater or lesser dimensions is formed between the base portion and the glass article, the size of which gap is very easily controllable however. The gap can in each case have an influence on the final positioning of the glass article on the conveyor belt, transversely to the longitudinal axis of the conveyor belt. The advantage of blowing against the cylindrical part of the glass article lies in a particularly good utilisation of the compressed air to achieve a sufficient suction effect.
During the pushing, the glass article is in contact with at least one thrust finger, which leads to a defined position of the glass article in the longitudinal direction of the conveyor belt.
The base portion includes a carrier rail having a horizontal longitudinal axis allowing supply channels that are arranged to carry compressed air in the carrier rail. The supply channels for each thrust finger each include an upper cross-passage and a lower cross-passage issuing respectively at an upper contact surface and at a lower contact surface of the carrier rail. Depending upon the desired height of the nozzle, a coupling member carrying the nozzle can be connected in a gas-tight manner either with the upper contact surface or with the lower contact surface. In each coupling member there is provided a connecting passage creating a permanent connection between the associated cross-passage and the nozzle. In this manner it is possible to achieve a very effective and flexible supplying of the jets with compressed air.
At least one thrust finger of each pocket is mounted on the associated coupling member, thus the thrust fingers participate in any possible setting movements of the coupling member. By virtue of this, a separate adjustment of the thrust fingers is superfluous.
Because each coupling member can be adjusted relative to the carrier rail in the directions of the longitudinal axis of the carrier rail it is possible to adjust the thrust fingers of adjacent pockets to match the spacing of the longitudinal axes of adjacent glass articles from one another.
These and further features and advantages of the invention will now be described in more detail with reference to a number of embodiments which are illustrated in the drawings.